At least some of the exemplary embodiments described herein relate to methods of using drag-reducing propping fibers as friction reducing agents and propping agents in low permeability subterranean formation operations, and treatment fluid compositions relating thereto.
Subterranean wells (e.g., hydrocarbon producing wells, gas producing wells, or water producing wells) are often stimulated by hydraulic fracturing treatments. In traditional hydraulic fracturing treatments, a treatment fluid, which may also function simultaneously or subsequently as a carrier fluid, is pumped into a portion of a subterranean formation at a rate and pressure sufficient to break down the formation and create one or more fractures therein. As used herein, the term “subterranean formation” and “formation” have the same meaning. Typically, particulate solids, such as graded sand, are suspended in a portion of the treatment fluid and then deposited into the fractures. The particulate solids, known as “proppant particulates,” “proppant,” or “propping particulates,” serve to prevent the fractures from fully closing once the hydraulic pressure is removed. By keeping the fractures from fully closing, the proppant particulates aid in forming conductive paths through which fluids produced from the formation may flow. The degree of success of a stimulation operation depends, at least in part, upon the porosity of the interconnected interstitial spaces between abutting proppant particulates, through which fluids may flow.
In the case of stimulating low permeability formations, such as shale reservoirs or tight-gas sands, increasing fracture complexity during stimulation may enhance the production of the formation. Low permeability formations, as described herein, tend to have a naturally occurring network of multiple interconnected micro-sized fractures referred to as “fracture complexity.” Such fracture complexity may be enhanced by stimulation (e.g., fracturing) operations to create new micro-fractures or enhance (e.g., elongate) existing micro-fractures. In such cases, the newly formed or enhanced micro-fractures may remain open without the assistance of proppant particulates due to imperfect closure of the micro-fractures after hydraulic pressure is removed. The inclusion of proppant particulates in these micro-fractures, new or natural, may increase permeability of the low permeability formation.
During subterranean formation operations (e.g., stimulation, proppant placement, and the like), aqueous treatment fluids are often pumped through tubulars (e.g., pipes, coiled tubing, etc.). A considerable amount of energy may be lost due to friction between the aqueous treatment fluid in turbulent flow and the formation, the wellbore, and or the tubulars located within the wellbore. For example, in stimulation operations, a treatment fluid may be viscosified and/or injected into a formation at a high flow rate to achieve sufficient fracturing and/or to serve as a carrier fluid. As the treatment fluid flows across the surfaces in the formation, the wellbore, and related tubulars, the frictional forces between the treatment fluid and surfaces are amplified relative to non-viscosified fluids under normal flow because of the increased viscosity or high flow rate of the treatment fluid. The amplified friction forces translate into a need for increasing the energy input to achieve the desired pressure and/or flow rate for the treatment fluid. Increasing energy input increases the cost of the fracturing operation. Moreover, the energy input necessary for stimulation of or proppant placement in low permeability formations that often require highly pressurized treatment fluids may be even more costly. As used herein, the term “wellbore” refers to wellbores of any configuration including, vertical wellbores and non-vertical wellbores (e.g., slant drilling of horizontal wells, and the like).
Accordingly, a need exists for a friction reducing agent that may also serve as a proppant particulate for use in low permeability subterranean formations.